Impact modified polyphenylene ether-polyamide compositions

ABSTRACT

Thermoplastic compositions comprised of compatible combinations of a polyphenylene ether resin and a polyamide resin and which require improved low temperature ductility can be impact modified with a modifying agent comprising a partially hydrogenated diblock copolymer of styrene and ethylene/propylene.

This is a continuation of application Ser. No. 228,249, filed Aug. 4,1988, now abandoned, which is a continuation of application Ser. No.837,474, filed Mar. 7, 1986, now abandoned.

FIELD OF THE INVENTION

Compositions comprising a combination of polyphenylene ether resin andpolyamide resin can be impact modified with a selectively hydrogenateddiblock copolymer of styrene and ethylene/propylene which isparticularly effective for thermoplastic applications requiring improvedlow temperature ductility.

BACKGROUND OF THE INVENTION

Polyphenylene ether resins have been modified with polyamide resins toprovide a wide variety of beneficial properties such as excellent heatresistance, chemical resistance, impact strength, hydrolytic stabilityand dimensional stability. The improved properties of polyphenyleneether-polyamide compositions have found great utility in thermoplasticapplications which take advantage of such properties. Exteriorautomotive applications such as body panels and wheel covers all benefitfrom the improved thermal properties of polyphenylene ether-polyamidecompositions (PPE/PA compositions). In typical automotive applicationssuch as a fender part, a satisfactory thermoplastic must be capable ofproviding satisfactory properties over a wide range of end-usetemperatures.

Although many important thermoplastic applications for PPE/PAcompositions require that the resin be impact modified to provideadequate performance, the ductile behavior of such reasons is oftenoverlooked.

Ductile behavior is an important physical property for thermoplastics inmany applications, but particularly for automotive parts which mayexperience extremely rigorous conditions at very low temperatures. Themode of failure for a part, whether ductile or brittle failure, at agiven temperature is also an important indication of the utility of thethermoplastic. Improvements in low temperature ductile-brittletransitions will increase the opportunity for polyphenyleneether-polyamide compositions to adequately service thermoplasticapplications where such properties are required or desired. Manyconventional, rubber-like impact modifiers offer advantages anddisadvantages but do not provide the range of ductile behaviorimprovement offered by the present invention. Conventional impactmodifiers for polyphenylene ether-polyamide compositions can be costlyand ineffective compared to the impact modification system describedherein.

It has now been discovered that polyphenylene ether-polyamidecompositions can be improved by combining the base resin with a modifiercomprised of a partially hydrogenated diblock copolymer of styrene andethylene-propylene in accordance with the description below. Suchcompositions exhibit the superior properties normally associated withcompatible polyphenylene ether/polyamide compositions as well asunexpectedly improved ductile behavior.

SUMMARY OF THE INVENTION

Thermoplastic compositions of the present invention are comprised of:

a. a base resin which is a compatiblized combination of a polyphenyleneether resin and a polyamide resin; and

b. an amount of an impact modifying agent effective for improving theductile behavior of such base resin and which is a selectivelyhydrogenated diblock copolymer of styrene and ethylene/propylene.

Preferred polyphenylene ether resins and polyamide resins as well asmeans for providing compatiblized combinations thereof are describedbelow.

In general it is desirable that the polyamide component comprise acontinuous phase in the overall composition and, therefore, typically atleast 35 percent by weight of the total PPE-polyamide-modifiercomposition will be comprised of the polyamide component. The remainderof the composition will be comprised of the PPE and diblock copolymermodifier, in typical weight ratios described below.

The preferred diblock modifying component is typically comprised of 20to 40 weight percent of a styrene block and 80 to 60 weight percent ofan ethylene/propylene block which can be erived from a rubbery blockwhich has been selectively hydrogenated to eliminate some or all of theresidual unsaturation contained in the rubbery block.

DESCRIPTION OF THE INVENTION

Polyphenylene ethers are a well known class of compounds sometimesreferred to as polyphenylene oxides. Examples of suitable polyphenyleneethers and processes for preparation can be found in U.S. Pat. Nos.3,306,874; 3,306,875; 3,257,357; and 3,257,358 which are eachincorporated by reference. Compositions of the present invention willencompass homopolymers, copolymers and graft copolymers obtained by theoxidative coupling of phenolic compounds. The preferred polyphenyleneethers used as base resins in compositions of the present invention willbe comprised of units derived from 2,6-dimethyl phenol. Alsocontemplated are PPE copolymers comprised of units derived from2,6-dimethyl phenol and 2,3,6-trimethyl phenol.

A particularly useful polyphenylene ether would bepoly(2,6-dimethyl-1,4-phenylene ether) having an intrinsic viscosity(I.V.) greater than, approximately 0.10 dl/g as measured in chloroformat 25° C. The I.V. will typically be between 0.30 and 0.50 dl/g.

The polyamide resins useful in the practice of the present invention area generic family of resins known as nylons, characterized by thepresence of an amide group (--CONH--). Nylon-6 and nylon-6,6 are thegenerally preferred polyamides and are available from a variety ofcommercial sources. Other polyamides, however, such as nylon-4,nylon-12, nylon-6,10, nylon-6,9 or others such as the amorphous nylonsmay be useful for particular polyphenylene ether-polyamide applications.

The polyamides can be provided by a number of well known processes.Nylon-6, for example, is a polymerization product of caprolactam.Nylon-6,6 is a condensation product of adipic acid andhexamethylenediamine. A nylon-6,6 having an average molecular weight ofapproximately 10,000 is especially preferred for many usefulpolyphenylene ether-polyamide thermoplastic applications. Preferredpolyamides will typically have a relative viscosity of at least 35, inaccordance with ASTM Test Method D789.

In U.S. Pat. No. 3,379,792, (incorporated herein by reference) Finholtprovided useful combinations of polyphenylene ether and polyamide, wherethe weight percent of the polyamide component did not exceed about 25percent. Beyond that proportion, noticeable decrease in properties wasattributed to the relative incompatibility of the two resins.

In preferred embodiments of the present invention, a compatibilizingagent may be employed in the preparation of the composition. Thetwo-fold purpose for using compatibilizing agents is to improve, ingeneral, the physical properties of the polyphenylene ether-polyamideresin, as well as to enable the use of a greater proportion of thepolyamide component. When used herein, the expression "compatibilizingagent" refers to those polyfunctional, compounds which interact witheither the polyphenylene ether, the polyamide or both. This interactionmay be chemical (e.g. grafting) or physical (e.g. effecting the surfacecharacteristics of the dispersed phases). In either instance theresulting polyphenylene ether-polyamide composition appears to exhibitimproved compatibility, particularly as evidenced by enhanced impactstrength, mold knit line strength and/or elongation. As used herein, theexpression "compatiblized polyphenylene ether-polyamide base resin"refers to those compositions which have been physically or chemicallycompatibilized with an agent as discussed above, as well as thosecompositions which are physically compatible without such agents, astaught in the Finholt patent mentioned earlier.

Examples of the various compatibilizing agents that may be employed inthe practice of the present invention include: a) liquid diene polymers,b) epoxy compounds, c) oxidized polyolefin wax, d) quinones, e)organosilane compounds and f) polyfunctional compounds as describedhereinafter.

Liquid diene polymers (a) suitable for use herein include homopolymersof a conjugated diene with at least one monomer selected from the groupconsisting of other conjugated dienes; vinyl monomer, e.g. styrene andalpha-methyl styrene; olefins, e.g. ethylene, propylene, butene-1,isobutylene, hexene-1, octene-1 and dodecene-1, and mixtures thereof,having a number average molecular weight of from 150 to 10,000preferably 150 to 5,000. These homopolymers and copolymers can beproduced by the methods described in, for example, U.S. Pat. Nos.4,054,612; 3,876,721 and 3,428,699 incorporated herein by reference andinclude, among others, polybutadiene, polyisoprene,poly(1,3-pentadiene), poly(butadiene-isoprene), poly(styrene-butadiene),polychloroprene, poly(butadiene-alpha methylstyrene),poly(butadiene-styrene-isoprene), poly(butylene-butadiene) and the like.

Epoxy compounds (b) suitable for use in the practice of the presentinvention include: (1) epoxy resins produced by condensing polyhydricphenols (e.g. bisphenol-A, tetrabromobispheno10A, resorcinol andhydroquinone) and epichlorohydrin; (2) epoxy resins produced bycondensing polyhydric alcohols (e.g. ethylene glycol, propylene glycol,butylene glycol, polyethylene glycol, polypropylene glycol,pentaerythritol and trimethylolethane and the like) and epichlorohydrin;(3) glycidyletherified products of monohydric alcohols and monohydricphenols including phenyl glycidylether, butyl glycidyl ether and cresylglycidylether; (4) glycidyl derivatives of amino compounds for example,the diglycidyl derivative of aniline, and (5) epoxidized products ofhigher olefinic or cycloalkene, or natural unsaturated oils (e.g.soybean) as well as of the foregoing liquid diene polymers.

Oxidized polyolefin waxes (c) are well known and a description thereofand processes for the production of the same are found in U.S. Pat. Nos.3,822,227 and 3,756,999 and German Patent Publications 3,047,915 and2,201,862, herein incorporated by reference. Generally, these areprepared by an oxidation or suspension oxidation of polyolefin. Anespecially preferred polyolefin wax is "Hoescht Wacks".

Quinone compounds (d) suitable for use herein are characterized ashaving in the molecule of the unsubstituted derivative at least one 6membered carbon ring; at least two carbonyl groups in the ringstructure, both of which may be in the same or, if more than one ring,different rings, provided that they occupy positions corresponding tothe 1,2- or 1,4-orientation of the monocyclic quinone; and at least twocarbon-carbon double bonds in the ring structure, said carbon-carbondouble bonds and carbonyl carbon-oxygen double bonds being conjugatedwith respect to each other. Where more than one ring is present in theunsubstituted quinone, the rings may be fused, non-fused or both:non-fused rings may be bound by a direct carbon--carbon double bond orby a hydrocarbon radical having conjugated unsaturation such as ═C--C═.

Substituted quinones are also within the scope of the present invention.The degree of substitution; where substitution is desired, may be fromone to the maximum number of replaceable hydrogen atoms. Exemplary ofthe various substituents that may be present on the unsubstitutedquinone structures include halogen, e.g. chlorine, bromine, flourine,etc., hydrocarbon radicals including branched and unbranched, saturatedand unsaturated alkyl, aryl, alkyl aryl and cycloalkyl radicals andhalogenated derivatives thereof; and similar hydrocarbons having heteroatoms therein, particularly oxygen, sulfur or phosphorous and whereinthe same connects the radical to the quionone ring (e.g. oxygen link).

Exemplary of the various quinones there may be given 1,2- and1,4-benzoquione; 2,6-diphenyl quionone; tetramethyldiquinone; 2,2'- and4,4'-diphenoquinone; 1,2-, 1,4- and 2,6-naphthoquinone; chloranils;2-chloro-1,4-benzoquinone; 2,6-dimethyl benzoquione and the like.

Organosilane compounds (e) suitable as compatibilizing agents arecharacterized as having in the molecule (a) at least one silicon atombonded to a carbon through an oxygen link and (b) at least onecarbon-carbon double bond or carbon-carbon triple bond and/or afunctional group selected from the group consisting of an amine group ora mercapto group provided that the functional group is not directlybonded to the silicon atom.

In such compounds, the C--O--Si component is generally present as analkoxyl or acetoxy group bonded directly to the silicon atom, whereinthe alkoxy or acetoxy group generally has less than 15 carbon atoms andmay also contain hetero atoms (e.g. oxygen). Additionally, there mayalso be more than one silicon atom in the compound, such multiplesilicon atoms, if present, being linked through an oxygen link (e.g.siloxanes), a silicon-silicon bond; or a bifunctional organic radical(e.g. methylene or phenylene groups).

Examples of suitable organosilane compounds include: gamma aminopropyltriethoxy silane, 2-(3-cyclohexenyl)ethyl trimethoxy silane;1,3-divinyl tetraethoxy silane; vinyl tris-(2-methoxyethoxy)silane;5-bicycloheptenyl)triethoxy silane and gamma mercapto propyl trimethoxysilane.

Finally, polyfunctional compounds (f) which may be employed ascompatibilizer in the practice of the present invention are of threetypes. The first type of polyfunctional compounds are those having inthe molecule both (a) a carbon-carbon double bond or a carbon-carbontriple bond and (b) at least one carboxylic acid, acid anhydride, acidhalide, anhydride, acid halide anhydride, acid amide, acid ester, imide,amino, or hydroxy group. Examples of such polyfunctional compoundsinclude maleic acid; maleic anhydride; fumaric acid; citraconic acid;itaconic acid; maleimide; maleic hydrazide; reaction products resultingfrom a diamine and maleic anhydride, maleic acid, fumaric acid, etc;dicholoro maleic anhydride; malic acid amide; unsaturated dicarboxylicacids (e.g. acrylic acid, butenoic acid, methacrylic acid,t-ethylacrylic acid, pentenoic acid); decenoic acids, undecenoic acids,dodecenoic acids, linoleic acid, etc.); esters, acid amides oranhydrides of the foregoing unsaturated carboxylic acids; unsaturatedalcohols (e.g. allyl alcohol, crotyl alcohol, methyl vinyl carbinol,4-pentene-1-ol, 1,4-hexadiene-3-ol, 3-butene-1,4-diol,2,5-dimethyl-3-hexene-2,5-diol and alcohols of the formulae C_(n)H_(2n-5) OH, C_(n) H_(2n-7) OH and C_(n) H_(2n-9) OH, wherein n is apositive integer up to 30), unsaturated amines resulting from replacingthe --OH group(s) of the above unsaturated alcohols with NH₂ groups; andfunctionalized diene polymers and copolymers. Of these, one of thepreferred compatibilizing agents for compositions of the presentinvention is maleic anhydride.

The second group of polyfunctional compatibilizer compounds suitable foruse herein are characterized as having both (a) a group represented bythe formula (OR) wherein R is hydrogen or an alkyl, aryl, acyl orcarbonyl dioxy group and (b) at least two groups each of which may bethe same or different selected from carboxylic acid, acid halide, acidanhydride, anhydride, acid halide anhydride, acid ester, acid amide,imido, amino and salts thereof. Typical of this group of compatibilizersare the aliphatic polycarboxylic acids, acid esters and acid amidesrepresented by the formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

wherein R is a linear or branched chain, saturated aliphatic hydrocarbonof from 2 to 20, preferably 2 to 10, carbon atoms; R^(I) is selectedfrom the group consisting of hydrogen or an alyl, aryl, acyl or carbonyldioxy group of 1 to 10, preferably 1 to 6, most preferably 1 to 4,carbon atoms, especially preferred is hydrogen; each R^(II) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 20 carbon atoms, preferably from 1 to 10carbon atoms; each R^(III) and R^(IV) is independently selected from thegroup consisting essentially of hydrogen or an alkyl or aryl group offrom 1 to 10, preferably from 1 to 6, most preferably 1 to 4, carbonatoms; m is equal to 1 and (n+s) is greater than or equal to 2,preferably equal to 2 or 3, and n and s are each greater than or equalto zero and wherein (OR^(I)) is alpha or beta to a carbonyl group and atleast two carbonyl groups are separated by 2 to 6 carbon atoms.Obviously, R^(I), R^(II), R^(III) and R^(IV) cannot be aryl when therespective substituent has less than 6 carbon atoms.

Illustrative of suitable polycarboxylic acids there may be given citricacid, malic acid, and agaricic acid; including the various commercialforms thereof, such as, for example, the anhydrous and hydrated acids.Of these, citric acid is another of the preferred compatibilizingagents. Illustrative of acid esters useful herein include for example,acetyl citrate and mono- and/or di- stearyl citrates and the like.Suitable acid amides useful herein include for example N,N'- diethylcitric acid amide; N,N'-dipropyl citric acid amide; N-phenyl citric acidamide; N-dodecyl citric acid amide; N,N'-didodecyl citric acid amide andN-dodecyl malic acid amide. Derivatives of the foregoing polycarboxylicacids are also suitable for use in the practice of the presentinvention. Especially preferred derivatives are the salts thereof,including the salts with amines and/preferably, the alkali and alkalinemetal salts. Exemplary of suitable salts include calcium malate, calciumcitrate, potassium malate and potassium citrate.

The third group of polyfunctional compatibilizer compounds suitable foruse herein are characterized as having in the molecule both (a) an acidhalide group, most preferably an acid chloride group and (b) at leastone carboxylic acid, carboxylic acid anhydride, acid ester or acid amidegroup, preferably a carboxylic acid or carboxylic acid anhydride group.Exemplary of compatibilizers within this group there may be giventrimellitic anhydride acid chloride, chloroformyl succinic anhydride,chloro formyl succinic acid, chloroformyl glutaric anhydride,chloroformyl glutaric acid, chloroacetyl succinic anhydride,chloroacetylsuccinic acid, trimellitic acid chloride and chloroacetylglutaric acid. Among these, trimellitic anhydride acid chloride ispreferred. Furthermore, it is especially preferred that compatibilizersof this group be prereacted with at least a portion of the polyphenyleneether whereby the compatibilizing agent is a PPE-functionalizedcompound.

Each of the foregoing compatibilizing agents are more fully described inU.S. Pat. No. 4,315,086; U.S. Pat. application Ser. Nos. 669,130;736,489 and 780,151 filed Nov. 7, 1984, May 20, 1985, and, Sep. 26,1984, respectively, and European Patent Application No. 04640,altogether herein incorporated by reference.

The foregoing compatibilizing agents may be used alone or in anycombination of one another. Furthermore, they may be added directly tothe melt blend or precompounded with either or both the polyphenyleneoxide and polyamide as well as with other resinous materials employed inthe preparation of the compositions of the present invention. With manyof the foregoing compatibilizing agents, particularly the polyfunctionalcompounds, even greater improvement in compatibility is found where atleast a portion of the compatibilizing agent is precompounded with allor part of the polyphenylene oxide. It is believed that suchprecompounding may cause the compatibilizing agent to react with thepolymer and, consequently, functionalize that polymer. For example, thepolyphenylene oxide may be precompounded with trimellitic acid chlorideanhydride to form an anhydride functionalized polyphenylene ether whichhas improved compatibility with the polyamide compared to anon-functionalized polyphenylene ether.

Where the compatibilizing agent is employed in the preparation of thecompositions of the present invention, the initial amount used will bedependent upon the specific compatibilizing agent chosen and thespecific polymeric system to which it is added. The examples belowdepict several suitable compatibilization methods used in the practiceof the present invention.

Those skilled in the art will be able to provide impact improvedcompositions comprising various proportions of the polyphenylene etherresin, the polyamide resin the compatibilizing agent, if required, andthe diblock copolymer impact modifier. In general, however, wherechemical resistance is a desirable property of the thermoplastic resin,it will ordinarily be necessary that the polyamide resin form acontinuous phase of the resin composition. Therefore, to avoid a phaseinversion whereby the polyamide phase is discontinuous, the preferredcompositions of the present invention will be comprised of a polyamideresin in an amount equal to or greater than approximately 35 percent byweight of the total composition (i.e. the PPE, PA, and diblock copolymercomponents taken together). The remaining components will be comprisedof the PPE and diblock copolymer impact modifier, and may togetheraccount for up to approximately 65 percent by weight of the totalresinous components of the composition.

A variety of useful polyphenylene ether-polyamide compositions can beprovided which include varying amounts of the diblock copolymermodifying agent. Typcially, improved properties, especially regardingthe ductile behavior of the plastic, will be noted when 1 to 30 parts byweight of the diblock copolymer are utilized per 100 parts of thepolyphenylene ether and polyamide components taken together.

As might be expected, lower amounts of the diblock copolymer modifierwould achieve little useful effect, whereas excess amounts could detractfrom the physical properties of the thermoplastic resin composition. Inpreferred compositions, approximately 5 to 25 parts of the diblockcopolymer modifier will be utilized per 100 parts by weight of the baseresin.

The diblock copolymer rubber additive useful in compositions of thepresent invention is a thermoplastic rubber comprised of an alkenylaromatic block which is typically a styrene block and anethylene-propylene block which had been derived from a partially orselectively hydrogenated block. These materials are commonly referred toas SEP diblocks. The weight ratio of the styrene block compared to therubber block may be varied to a considerable degree and many usefulcompositions can be provided without difficulty. Typically, commerciallyavailable diblock copolymers having a styrene:rubber ratio of 20 to 40parts styrene: 80 to 60 parts rubber will be preferred. These materialsmay be made by the anionic polymerization of the respective blockcomponents, followed by selective hydrogenation. Selective hydrogenationrefers to the hydrogenation of some or all of the unsaturated sites onthe rubber component as opposed to hydrogenation of the aromatic styrenecomponent. This selective hydrogenation process is one feature whichdistinguishes SEP diblock from conventional SBR rubber compounds. TheSEP diblock copolymers having selectively hydrogenated rubber blocksexhibit improved properties in compositions of the present invention,especially as compared to conventional non-hydrogenated diblockcopolymers, as well as hydrogenated and non-hydrogenated triblock andmultiblock copolymers.

Useful selectively hydrogenated diblock copolymers of thestyrene-ethylene/propylene type are commercially available in a varietyof grades from Shell Chemical Co. Commercial grades typically containminor amounts of antioxidants and stabilizers. For purposes of thepresent disclosure it is intended that the selectively hydrogenateddiblock copolymer of the styrene-ethylene/propylene type encompassesthose similar diblock copolymers which may be provided from a variety ofstarting materials, in particular, selectively hydrogenated diblockcopolymers of styrene and isoprene.

The preparation of selectively hydrogenated block copolymers of alkenylaromatic polymers and diene polymers is described in numerous patents,including U.S. Pat. Nos. 4,085,163 and 4,041,103 (both incorporated byreference) which also describe the use of such copolymers in polyamideresins. Their use in compatible polyphenylene ether-polyamide resinsystems was not forseen nor was the improvement in such systems of theductile behavior noted in the present invention.

The foregoing constituent ingredients can be compounded and molded byconventional means. The order of mixing and degree of shear experiencedduring extrusion can be varied. It would be expected that the physicalproperties could vary as such processing conditions are varied. Thoseskilled in the art will be able to achieve optimum processing conditionswhich may vary for different thermoplastic applications.

Thus in one instance, each of the ingredients could be blended andextruded at once, thereby providing thermoplastic resin having aparticular property profile. Alternatively it may be desirable topre-blend or precompound some of the ingredients while the remainingingredients are charged later in a compounding or extrusion process.

In one embodiment, the polyphenylene ether, with or without acompatibilizing agent, could be pre-compounded with the diblockcopolymer impact modifier. Thereafter, the polyamide resin could becharged to the extruder downstream, at a point sufficient to provideadequate mixing but with minimum risk of degradation due to excess heat.

Additionally, it is expected that conventional additives such asfillers, pigments and flame retarding compounds and metal synergists canbe incorporated in the thermoplastic compositions of the presentinvention, thereby providing a variety of useful products.

Unless otherwise noted, all formulations in the following examples aregiven in parts by weight. These examples should not be considered aslimiting the scope of the invention in any way.

EXAMPLES 1 AND 2

Several thermoplastic blends in accordance with the present inventionwere prepared and compared to compositions having conventional impactmodifiers as described in Table 1. The polyphenylene ether waspoly(2,6-dimethyl-1,4-phenylene ether) having an intrinsic viscosity of0.45 as measured in chloroform at 25° C. The polyamide component wasnylon 6, designated NYCOA 471 from Nylon Company of America. Except fortwo control blends, each blend in this series contained 50 parts byweight polyphenylene ether, 40 parts nylon 6, 0.5 parts of maleicanhydride compatibilizing agent, and 10 parts of the designated rubberadditive.

The compositions were compounded by blending the requisite constituentswhich were extruded on a Werner & Pfleiderer 28 mm twin screw extruderhaving set temperatures over several stages of450°/530°/535°/540°/550°/560° F., no vacuum, at 280 rpm.

The compositions were molded on a Newbury three ounce injection moldingmachine having a barrel set temperature of 550°-580° F., a mold settemperature of 150°-160° F., and a total cycle time of 40 seconds. Themode of failure in the Dynatup (DYN) falling dart impact test ischaracterized as B (brittle), B-D (brittle-ductile), or D (ductile)based on disk response to impact. Dynatup results are reported ininch-pounds at maximum load (ML) and total energy (TE), at roomtemparture as well as -40° F.

                                      TABLE 1                                     __________________________________________________________________________                    MALEIC  TEN.YLD.                                                                             TUS TE IZOD HDT DYN  DYN                       SAMPLE                                                                              RUBBER    ANHYDRIDE                                                                             Kpsi   Kpsi                                                                              %  ft.lbs./in.                                                                        66 psi                                                                            ML   TE                        __________________________________________________________________________    A*    none      none    6.8    6.8  5 0.8  367  7    12                       B*    none      0.5     10.9   8.1 43 1.0  375  42   43                       C*    SEBS triblock.sup.(a)                                                                   0.5     8.1    6.9 41 2.1  370 360  516                       D*    SEBS triblock.sup.(b)                                                                   0.5     6.6    6.6 38 3.2  363 312  524                       E*    SEBS triblock.sup.(c)                                                                   0.5     5.6    5.5 33 2.0  353  72   72                       1     SEP diblock.sup.(d)                                                                     0.5     8.8    7.1 36 9.6  366 378  558                       2     SEP diblock.sup.(e)                                                                     0.5     8.2    6.9 52 12.1 369 384  576                       F*    SBS triblock.sup.(f)                                                                    0.5     8.2    7.2 72 7.1  365 408  583                       G*    SBS triblock.sup.(g)                                                                    0.5     7.9    7.1 54 6.4  362 396  576                       H*    SBS rubber.sup.(h)                                                                      0.5     9.0    7.4 52 4.5  351 348  538                       __________________________________________________________________________                            FAILURE                                                                              DYN  DYN  FAILURE                                                                              FLOW                                            SAMPLE                                                                              MODE   ML-40F                                                                             TE-40F                                                                             MODE-40F                                                                             CHANNEL(")                    __________________________________________________________________________                      A*    B      B     11  B      23.5                                            B*    B       36   36  B      26.75                                           C*    B-D     24   24  B      25.75                                           D*    B       32   34  B      26.25                                           E*    B       12   12  B      29                                              1     D      468  576  B      26.5                                            2     D      444  564  B      25.75                                           F*    D      492  564  B      25.25                                           G*    D      516  598  B      25                                              H*    D      384  444  B      26.75                         __________________________________________________________________________     *Samples A-H are comparative examples                                         .sup.(a) Kraton G 1651, Shell Chemical selectively hydrogenated               styreneethylene/butylene-styrene triblock copolymer                           .sup.(b) Kraton G 1652, Shell Chemical selectively hydrogenated               styreneethylene/butylene-styrene triblock copolymer                           .sup.(c) Kraton G 1657, Shell Chemical selectively hydrogenated               styreneethylene/butylene-styrene triblock copolymer                           .sup.(d) Kraton GX 1701, Shell Chemical, selectively hydrogenated             styreneethylene/propylene diblock copolymer styrene: rubber ratio is          approximately 37:63                                                           .sup.(e) Kraton GX 1702, Shell Chemical, selectively hydrogenated             styreneethylene/propylene diblock copolymer styrene: rubber ratio is          approximately 27:73                                                           .sup.(f) Kraton D 1101, Shell Chemical, styrenebutadiene-sytrene triblock     copolymer                                                                     .sup.(g) Kraton D 1102, Shell Chemical, styrenebutadiene-styrene triblock     copolymer                                                                     .sup.(h) Stereon 840A, Firestone Chemical styrenebutadiene multiblock         copolymer                                                                

It will be evident from the foregoing that several physical propertiesof compatible polyphenylene ether-polyamide compositions can be improvedupon the addition of the S-E/P diblock copolymer modifier utilized bythe present invention.

EXAMPLES 3-6

Blends were prepared as above using 24.5 parts polyphenylene ether, 24.5parts PPO-TAAC compatibilizing agent, 41 parts nylon 6,6, and either 5or 10 parts of the rubber component. The PPO-TAAC compatibilizing agentwas the reaction product of a polyphenylene ether resin in solution andtrimellitic anhydride acid chloride, which is thereafter isolated anddried. This PPO-TAAC compound is a functionalized polyphenylene either,capable of compatibilizing a polyphenylene ether-polyamide compositionand which, in this example, replaces 24.5 parts of the conventionalpolyphenylene ether. Table 2, describes the results where it can be seenthat acceptable properties can be achieved with reduced rubber content,resulting in higher heat distortion values and lower costs. All modes offailure were of the ductile type.

                                      TABLE 2                                     __________________________________________________________________________                        Notch                                                                             Dynatup                                                                            Tensile                                                                             HDT                                        Example                                                                            Rubber Type (parts)                                                                          Izod                                                                              Impact                                                                             Elongation                                                                          66 psi                                     __________________________________________________________________________     I*  Unsaturated S-B-S (10) .sup.(a)                                                              8.8 492  44    370                                        3    Saturated SEP diblock (10) .sup.(b)                                                          10.4                                                                              552  67    387                                        4    Saturated SEP diblock (5) .sup.(b)                                                           4.4 529  43    391                                        5    Saturated SEP diblock (10) .sup.(c)                                                          9.8 551  53    381                                        6    Saturated SEP diblock (5) .sup.(c)                                                           3.4 491  37    392                                        __________________________________________________________________________     *Comparison                                                                   .sup.(a) Kraton D 1102 Triblock                                               .sup.(b) Kraton GX 1702 SEP diblock                                           .sup.(c) Kraton GS 1701 SEP diblock                                      

EXAMPLES 7-10

Further blends were prepared, as above, using 0.70 parts citric acid asthe compatibilizer in compositions containing 49 parts polyphenyleneether, 41 parts nylon 6,6 and between 5 to 15 parts of the rubbercomponent. These blends contained 0.30 parts Inrganox 1076 and 0.10parts KI stabilizers. These citric based blends showed improvementsusing the SEP diblock in place of conventional triblock rubbers. Inthese blends the mode of failure was brittle.

                  TABLE 3                                                         ______________________________________                                        EX-                      NOTCH    DYNATUP                                     AMPLE  RUBBER TYPE (Parts)                                                                             IZOD     IMPACT                                      ______________________________________                                        J*     Unsaturated SBS triblock                                                                        2.8      420                                                (10) .sup.(a)                                                          7      Saturated SEP diblock (5) .sup.(b)                                                              2.5      402                                         8      Saturated SEP diblock (5) .sup.(b)                                                              2.5      402                                         9      Saturated SEP diblock                                                                           7.1      341                                                (10) .sup.(b)                                                          10     Saturated SEP diblock                                                                           10.5     342                                                (15) .sup.(b)                                                          ______________________________________                                         *Comparison                                                                   .sup.(a) Kraton D 1102 triblock                                               .sup.(b) Kraton GX1702 SEP diblock                                       

EXAMPLE 11

It has also been unexpectedly found that the saturated diblock rubbersutilized in the present invention provided excellent heat agingcharacteristics. This effect was not expected since previous work withsaturated SEBS triblock rubber had shown no improvement in this regard.In these examples, 10 parts of the indicated rubber were used inpolyphenylene ether-polyamide blends containing 49 parts PPE 0 and 41parts polyamide (Nylon 6,6), compatibilized with 0.7 parts citric acid.The SBS triblock rubber was Kraton D 1102 and the SEP saturated diblockrubber was Kraton GX1702. These blends contained 0.1 parts KI, 0.3 partIrganox 1076 hindered phenol, and 4 parts TiO₂. Table 4 describes theresults of this series of blends where mode of failure characteriationsare given along with the Dynatup impact figures. In this series, Brepresents brittle failure, S represents a part which split upon impactindicating intermediate ductility.

                                      TABLE 4                                     __________________________________________________________________________                      Initial                                                                            Dynatup Impact                                                                         350° F.                                                                    350° F.                                                                    375° F.                                                                    325° F.                    Example                                                                            Rubber Type  N. Izod                                                                            (initial)                                                                              2 hr                                                                              4 hr                                                                              2 hr                                                                              4 hr                              __________________________________________________________________________    K*   SBS Unsaturated Triblock                                                                   2.8  420 S/B  480S                                                                              156S                                                                              144S                                                                              120B                              11   SEP Saturated Diblock                                                                      7.1  336S     480S                                                                              324S                                                                              456S                                                                              444S                              __________________________________________________________________________

I claim:
 1. A thermoplastic composition comprisingA. a base resincomprising a compatibilized combination of a polyphenylene ether resin,polyamide resin, and a compatibilizing agent selected from the groupconsisting of: maleic anhydride, fumaric acid, citric acid, malic acid,and reaction products of a polyphenylene ether and trimellitic anhydrideacid chloride, and B. a property improving amount of a selectivelyhydrogenated diblock copolymer of the A-B type wherein block A is analkenyl aromatic polymer and block B is an ethylene-propylene polymer.2. A composition as in claim 1 wherein said compatible base resin iscomprised of (a.) 5 to 95 weight percent polyphenylene ether resin and(b.) 95 to 5 weight percent polyamide resin, based upon the weight of a.and b. together.
 3. A composition as in claim 2 wherein said polyamideresin constitutes a continuous phase in an amount greater than,approximately, 35 weight percent of the resinous components.
 4. Acomposition as in claim 1 wherein said polyphenylene ether resin is apolymer or copolymer comprised of 2,6-dimethyl phenol units and2,3,6-trimethyl phenol units.
 5. A composition as in claim 4 whereinsaid polyphenylene ether is poly(2,6-dimethyl-1,4-phenylene ether).
 6. Acomposition as in claim 1 wherein said polyamide resin is selected fromthe group consisting of polyamide 6, polyamide 6,6, polyamide 4,polyamide 12, polyamide 6,10, polyamide 6,9, amorphous nylons, ormixtures of more than one of the foregoing.
 7. A composition as in claim1 wherein said diblock copolymer is comprised of, approximately, 20 to40 weight percent styrene and 80 to 60 weight percent ethylene-propylenepolymer based upon the weight of both blocks taken together.
 8. Acomposition as in claim 1 wherein said diblock copolymer comprises,approximately, 1 to 30 parts by weight based upon the total weight ofbase resin.
 9. A composition as in claim 6 wherein said polyamide resinis selected from the group consisting of polyamide 6 and polyamide 6,6.10. A composition as in claim 9 wherein said polyamide is comprised ofpolyamide 6,6 having an average molecular weight of approximately10,000.
 11. A composition as in claim 1 wherein said polyamide has arelative viscosity of at least about 35, as determined in accordancewith ASTM Test Method D
 789. 12. A composition as in claim 1 wherein thepolyphenylene ether has an intrinsic viscosity greater than about 0.10dl/g as measured in chloroform at 25° C.
 13. A composition as in claim12 wherein said polyphenylene ether has an intrinsic viscosity ofbetween about 0.30 and 0.50 dl/g.
 14. A composition as in claim 8wherein said diblock copolymer comprises from about 5 to about 25 partsby weight based upon the total weight of base resin.
 15. A compositionas in claim 1 wherein component (A.) is comprised of about 50 parts byweight polyphenylene ether, about 40 parts by weight nylon 6 and about0.5 parts by weight of maleic anhydride, and component (B.) is comprisedof about 10 parts by weight of a saturated styrene-ethylene/propylenediblock copolymer.
 16. A composition as in claim 1 wherein component(A.) is comprised of about 24.5 parts by weight polyphenylene ether,about 24.5 parts by weight PPO-TAAC and about 41 parts by weight nylon6,6 and component (B.) is comprised of from about 5 to about 10 parts byweight of a saturated styrene-ethylene/propylene diblock copolymer. 17.A composition as in claim 1 wherein component (A.) is comprised of 49parts by weight polyphenylene ether, 41% parts by weight nylon 6,6 and0.70 parts by weight citric acid and component (B.) is comprised of fromabout 5 to about 15 parts by weight of a saturatedstyrene-ethylene/propylene diblock copolymer.
 18. A composition as inclaim 1 wherein component (A.) comprises 49 parts by weightpolyphenylene ether, 41% parts by weight polyamide 6,6 and 0.7 parts byweight citric acid and component (B.) comprises 10 parts by weight of asaturated styrene-ethylene/propylene diblock copolymer.
 19. Acomposition as in claim 1 wherein said base resin is compatibilized bythe use of citric acid.
 20. A composition as in claim 1 wherein saidbase resin is compatibilized by the use of maleic anhydride.
 21. Acomposition as in claim 1 wherein said base resin is compatibilized bythe use of PPO-TAAC.
 22. A composition as in claim 15 wherein thesaturated styrene-ethylene/propylene diblock copolymer has astyrene:rubber ratio of from about 27:73 to about 37:63.